Underwater mountains vital to climate, ocean currents

An undersea mountain passage near Antarctica may provide valuable information about regulating Earth's climate and ocean currents, British researchers said. The researchers found seawater from mid- and deep-depths mixes forcefully as it pours over undersea mountains in Drake Passage, the University of Exeter said Wednesday in a release. The research offers insight for climate models that, until now, lacked detailed information on ocean mixing crucial to provide accurate long-term climate projections, the university said. The project was jointly conducted by the University of Exeter, the University of East Anglia, the University of Southampton, the Woods Hole Oceanographic Institution, the British Antarctic Survey and the Scottish Association for Marine Science. Ocean mixing transfers carbon dioxide from the atmosphere to the deep sea and controls the rate at which the ocean absorbs carbon dioxide, the university said. Ocean mixing affects climate, for example when an increase in the rate of mixing allows the ocean to transfer more heat toward the poles. The researchers measured mixing in the Antarctic Ocean by releasing an inert chemical tracer into the Southeast Pacific, and tracking the tracer for several years as it went through Drake Passage to observe how quickly the ocean mixed. "A thorough understanding of the process of ocean mixing is crucial to our understanding of the overall climate system," said Andrew Watson, a professor at the University of Exeter. "Our study indicates that virtually all the mixing in the Southern Ocean [Antarctic Ocean] occurs in Drake Passage and at a few other undersea mountain locations. Our study will provide climate scientists with the detailed information about the oceans that they currently lack."